notes

The "percussion cap," introduced around 1830, was used to make muzzle-loading rifles fire reliably under any weather condition. (It replaced the flint.) The firearm's hammer would strike the cap, which would ignite the gunpowder, which would expel the bullet. The percussion cap gave way to the primer in modern breechloaded (rear-loaded) firearms. The primer is attached to the back end of the cartridge.